Hello. I don't know how to do this(Doh)

A = {$\displaystyle (x_1,x_2): x_1=0, 0 \leq x_2 \leq 1$}

B = {$\displaystyle (x_1,x_2): x_2=2, 0 \leq x_1 \leq 1$}

Describe A+B and A-B.

Thank you.

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- Oct 17th 2011, 08:44 AMLolytaDescribe A + B
Hello. I don't know how to do this(Doh)

A = {$\displaystyle (x_1,x_2): x_1=0, 0 \leq x_2 \leq 1$}

B = {$\displaystyle (x_1,x_2): x_2=2, 0 \leq x_1 \leq 1$}

Describe A+B and A-B.

Thank you. - Oct 17th 2011, 08:55 AMTheChazRe: Describe A + B
Well, these are line segments...

Do you know what "+" and "-" mean in this context? - Oct 17th 2011, 08:57 AMalexmahoneRe: Describe A + B
- Oct 17th 2011, 09:12 AMTheChazRe: Describe A + B
- Oct 17th 2011, 09:15 AMalexmahoneRe: Describe A + B
- Oct 17th 2011, 09:17 AMalexmahoneRe: Describe A + B
- Oct 17th 2011, 12:15 PMLolytaRe: Describe A + B
- Oct 17th 2011, 12:24 PMPlatoRe: Describe A + B
- Oct 18th 2011, 06:01 AMLolytaRe: Describe A + B
- Oct 18th 2011, 06:25 AMPlatoRe: Describe A + B
So it is coordinate operations.

Rewrite the**B**set to make the answer clearer.

A = {$\displaystyle (x_1,x_2): x_1=0, 0 \leq x_2 \leq 1$}

B = $\displaystyle \{(x_1,x_2):0 \leq x_1 \leq 1, x_2=2\}$

Now

$\displaystyle A+B=\{x_1,x_2): 0\le x_1\le 1, 2 \leq x_2 \leq 1\}$

$\displaystyle A-B=\{x_1,x_2): -1\le x_1\le 0, -2 \leq x_2 \leq -1\}$ - Oct 18th 2011, 06:26 AMTheChazRe: Describe A + B
- Oct 18th 2011, 08:38 AMLolytaRe: Describe A + B
Thanks a lot to everyone :)